#include <stdio.h>
#include <string.h>

int main(int argc,char *argv[])
{
    if(argc!=2)
    {
        printf("Usage: %s [-a|-b|-c]\n",argv[0]);
        return 1;
    }
    const char* arg=argv[1];
    if(strcmp(arg,"-a")==0)
        printf("这是功能1\n");
    else if(strcmp(arg,"-b")==0)
        printf("这是功能2\n");
    else if(strcmp(arg,"-c")==0)
        printf("这是功能3\n");
    else
        printf("Usage: %s [-a|-b|-c]\n",argv[0]);
    return 0;
}
